I'm still trying to develope uses for this idea, but here's what I have so far:
Formation: when the player creates an ice world map, rivers of either methane or liquid nitrogen spawn randomly on the surface of the ground. Rovers and queens can fly over the rivers just like lava and water, and the rivers are permanently fixed, just like the water rivers on the earth like planet are fixed.
Resource and uses: The rivers would yield liquid nitrogen, which as we know is good for electronics. It would also come in handy if bast decides to add a thermal feature to terraforming, so it could be used to reduce planetary heat while lava could be used to increase it. liquid nitrogen, when combined with microchips, could be made into superconductors. Such superconductors could be used to replace the need for chips in bigger buildings to come for humans, and maybe some buildings that already exist, like the AI training facility, fantasy land arcology, and hall of congress. Liquid nitrogen generators could be built on non-ice worlds and would consume the largest amount of atmosphere to produce liquid nitrogen.
Main reason for idea: I mainly wanted to share this idea because the ice world was looking rather blank and featureless aside from the nearly invisible ice deposits scattered around. Bast was talking about wanting to add multiple types of terrain to the game to make it look better, which was why he made the water and lava textures, so I figured that a liquid nitrogen river would make a beautiful feature on the ice world and would be a unique advantage to ice world colonies since the supply would be unlimited as long as the atmosphere is under 1 million.